Dry working black image compositions comprising organic halogen compounds and ethylene compounds



United States Patent 3,510,304 DRY WORKING BLACK IMAGE COMPO- SITIONSCOMPRISING ORGANIC HAL- OGEN COMPOUNDS AND ETHYLENE COMPOUNDS Harry L.Fichter, Jr., Lakewood, and James M. Lewis, Cleveland, Ohio, assignorsto Horizons Incorporated, a division of Horizons Research Incorporated,a corporation of Ohio No Drawing. Filed Dec. 22, 1966, Ser. No. 603,731Int. Cl. G03c 5/24 US. CI. 96-48 7 Claims ABSTRACT OF THE DISCLOSUREThis application describes a photosensitive composition which prints outdirectly as a black or near neutral image When exposed photographicallyand which has a greatly improved speed.

This invention relates to photosensitive compositions from which a blackor near neutral image is obtained as a direct printout or as the resultof the application of heat to said composition after it has beenphotographically exposed. More particularly, it relates tophotosensitive compositions having improved photographic speed ascompared with prior art compositions and which have totally dry workingcharacteristics.

The invention also relates to photosensitive compositions from which ablack or near neutral positive image is obtained as a direct printout byfirst exposing the composition to a sensitizing dose of radiation andthen photographically exposing the composition to a pattern of inferredradiation having wavelengths longer than 6500 Angstrom units.

Photosensitive compositions which are believed to be based on freeradicals are described in a large number of patents and patentapplications and in technical articles published by HorizonsIncorporated and a list of issued United States Patents is appendedbelow for the purpose of incorporating their disclosures herein, byreference.

Some of the listed patents and publications describe free radicalphotographic systems which are dry fixing, i.e. in which the imageobtained after exposure is fixed and rendered insensitive to light bytotally dry means. Others of the listed patents and publicationsdescribe free radical photographic systems which yield a black image ornear neutral image.

A specific object of this invention is to provide a dry workingphotographic composition yielding a black or near neutral image as adirect printout or as the result of the application of heat to saidcomposition after it has been photographically exposed and particularlyto compositions having a greatly improved photographic speed as comparedwith prior art compositions having totally dry working characteristics.

With the exception of color photographic printing or where a specificcolored image is desired for display purposes, virtually every practicalapplication of the above noted free radical photographic systems prefera black or near black image color. Such contemplated uses include:oflice photoc py; microfilm retrieval systems; photographic printing,e.g. portraiture proofing; and even such military uses as themultigeneration aerial reconnaissance printing described in PS&E, vol.IX, No. 2, pp. 133-137, 1965; and all such uses demand a suitable blackimage produced without recourse to wet processing.

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UNITED STATES PATENTS PUBLICATIONS Photographic Science and Engineering,vol. 5, No. 2, March-April 1961, pp. 98-103.

Photographic Science and Engineering, vol. 8, No. 2, March-April 1964,pp. 91-95.

Photographic Science and Engineering, March-April 1964, pp. 95-103.

Photographic Science and Engineering,

March-April 1965, pp. 133-137.

The neutral image, dry working characteristics of the compositionsherein described are particularly important in certain of the aboveuses, since the use of a Wet Working system in high speed aircraft orspace vehicles is almost inconceivable. One such use whose feasibilityhas been established is the preparation of multigeneration printing ofaerial reconnaissance negatives as described in the above notedpublication. When a military reconnaissance aircraft photographs atarget, the negative resulting from that photograph is developed andreproduced through as many as four generations for determination of theintelligence revealed in the photograph. The original negative isprinted only once and then is stored in the archives. All subsequentprints are made from the second generation prepared from the originalnegative. Conventional silver halide systems are not completely suitablefor this multigeneration printing purpose, since the image is granular(particulate) and consequently each subsequent generation losesinformation which may be valuable in strategic decisions made from theuse of these photographs. Free radical photo-systems being molecularrather than granular have almost unlimited resolution particularly whencoated in thin layers, (about 4 to 5 microns thick), to take advantageof the geometry of present printer processors and their light sources.Free radical photographic systems have been established to be anexcellent medium for these multigeneration aerial reconnaissanceprintings, especially photosensitive free radical compositions based onthe teachings of United States Patent 3,109,736 and described inPhotographic Science and Engineering, vol. IX, No. 2, pp. 133-137, forMarch and April, 1965, under the title of New Photographic Processes,No. 4, The Cyanine Base Free Radical Photosystem-A Panchromatic BlackImage High Resolution Printout Film. The compositions described yieldexcellent jet black images and retain high latitude multigenerationprinting through four generations, with the minimum loss ofintelligence. However, the compositions are not dry working, but requirea solvent rinse after exposure to render the image fixed and stable toambient light.

Photointerpreters who evaluate these aerial reconnaissance photographstraditionally have been schooled in vol. 8, No. 2,

vol. 9, N0. 2,

the use of black image materials and are reluctant to use other colors.Hence the need for a dry working black image system to be used foraerial reconnaissance multigeneration printing.

One preferred composition from which hand coatings were made at .0015inch wet thickness on raw polyester film and thereafter evaluated asindicated below consisted of the following:

1,1-bis(p-dimethylaminophenyl)ethylene*-50 mg. Iodoform200 mg.

4-Picoline-1-oxide5 mg. 2,6-di-t-butyl-p-cresol-25 mg.Triphenylstibine-l mg.

Polystyrene 10% in benzene3 cc.

Acetonel cc.

Benzene-1 cc.

The composition is prepared by bringing the several constituentstogether in a suitable solvent system under a safelight or in totaldarkness and, after thoroughly mixing the composition, applying it to asolid substrate such as baryta paper or a film of polyester, glass orother suitable support.

After the composition has been laid down as a thin film, it is permittedto dry in air, in the dark or under a safelight, and then it isphotographically exposed to the equivalent of 0.01 watt seconds/cm. andheat fixed for 5-10 minutes at 135 C.-150 C. in moving air, whereby avery stable dense near black image was observed in the exposed areas.With this amount of exposure, maximum density of about 1.0 is achievedand the heated film is completely fixed, i.e. the image and backgrounddo not change upon further exposure to light. Increasing the exposure tothe equivalent of 0.1 watt second/cm. gave maximum densities in excessof 2.0 in the 14th step of a 21 step tablet. While not wishing to bebound by any specific explanation as to the function of each of theseveral constituents, it is believed that it is the dimethylaminophenylsubstituted ethylene which contributes to the formation of a black ornear neutral image when acted on by the products which result when theiodoform is exposed to a suitable dose of radiant energy. Instead of thegroup in this compound, an

group in which R and R are each alkyl or aryl or in which one of R and Ris H, could be present.

The function of the 4-picoline-N-oxide in the composition appears to bethat of an organic oxidizing agent which acts as a speed promoter incompositions containing a leuco compound.

The triphenylstibine and 2,6-di-t-butyl-p-cresol appear to act asstabilizers and prevent oxidation or degradation of the color formersduring the exposure and the subsequent heating of the composition whenin the form of a photosensitive film. The use of these compounds isdescribed in other issued patents and/ or copending patent applicationsfiled on behalf of the applicants assignee.

Binders for these compositions can be chosen from any one of a number ofbinders described in the patents already issued on free radicalphotographic compositions. Polystyrene, polyvinyl chloride,styrene-acrylonitrile copolymers, ethyl cellulose both G type and Ntype, cellulose acetate butyrate, polyvinyltoluene, butadiene-styrenecopolymers, the copolymer of polyvinyl chloride and vinylisobutyl ether,have all been used successfully in the practice of this invention. Thechoice of binder, however, produces considerable variation inphotographic speed and image color. All of the foregoing binders gave aneutral to black image.

Various substitutions may be made in the above formulation withoutdeparting from the intended scope of the invention.

For instance, other ethylene compounds may be used in place of thedimethylaminophenyl ethylene compound of the specific example includingother substantially colorless ethylene compounds represented by thegeneral formula wherein R and R each represent a p-dialkylaminophenylgroup in which the alkyl groups are selected from the group consistingof methyl and ethyl, and each of R and R represent a monovalent materialselected from the group consisting of H, halogen, alkyl, aryl, and othermonovalent groups which do not interfere with the resonance of theethylenic' double bond connecting the two carbon atoms.

For instance, instead of polystyrene in benzene, other film formingbinders can be used. Particularly preferred are polystyrene withmolecular weights above 100,000 (e.g. about 223,000) and abutadiene-styrene copolymer sold as Pliolite-S-SA (Goodyear ChemicalCo.).

Further, instead of triphenylstibine, other triaryl Group V compoundsmay be used, such as triphenylarsine, phosphine or bismuthine, asdescribed in United States Patent 3,275,443 issued Sept. 27, 1966, toEugent Wainer.

Similarly, it is possible to use other organic halogen compounds asdescribed in US. Patent 3,042,515 issued July 3, 1962, to Eugene Wainer,instead of the preferred iodoform.

Instead of iodoform, the free radical source may be any compoundrepresented by the general formula wherein each X represents an iodine,bromine or chlorine atom and not all of the Xs need be the same, and Arepresents a monovalent substance taken from the group consisting of H,Cl, Br, I, alkyl, aryl, aroyl, and the like.

Finally, it should be noted that although the proportions given in thepreceding example are believed to give optimum results for the specifiedconstiutents, the percentage of the individual constituents can bevaried over a considerable range, depending in some instances on thesolubility of the specific ingredient and in others on the nature andamount of the other compounds present in the formulation and on theresults desired.

With the formulation given above, proportions which have been foundsuitable are as follows: (parts by weight) Mg.1,1-bis-p-dimethylaminophenyl ethylene 1-100 4-picoline-N-oxide 01-10 Triphenylstibine 0.1-20 2,6-di-t-butyl-p-cresol 0.1-50 Iodoform -4000Hand coatings 0.0015 inch wet thickness were made of the above definedpreferred composition on raw polyester film and after the coatings hadbeen given a blanket exposure for 1 to 3 seconds to light from a 250watt reflector lamp, the distance from the lamp to the plane of the filmbeing inches, the sensitized film was exposed photographically to theequivalent of 5 to 10 watt seconds/ sq. cm. of radiation having wavelengths longer than 6500' angstrom units, whereby an image printed outdirectly, which was intensified and rendered stable by heat fixing at135 C.-150 C. for about 5 minutes in moving air.

Having now described a preferred embodiment of this invention, it is notintended that it be limited except as may be required by the appendedclaims.

We claim:

1. A photosensitive composition comprising:

(a) an organic halogen compound having at least three halogen atomsattached to a terminal carbon atom; and

(b) a substantially colorless ethylene compound represented by theformula wherein R and R each represent a p-dialkylaminophenyl group inwhich the alkyl groups are selected from the group consisting of methyland ethyl, and each of R and R represents a monovalent material selectedfrom the group consisting of H, halogen, alkyl, aryl, and othermonovalent groups which do not interfere with the resonance of theethylenic double bond connecting the two carbon atoms;

said constituents being present in proportions which yield a nearneutral or black image when reacted with the products resulting from thephotolytic exposure of said organic halogen compound; and

(c) a support for said composition.

2. The composition of claim 1 including at least one additional compoundwhich enhances the formation of the direct printout image and which isselected from the group consisting of picoline-l-oxide, triarylcompounds of an element selected from the group consisting of Sb, As, Biand P, and di-t-butyl-p-cresol.

3. The composition of claim 1 in which (b) is 1,1-bis-(p-dimethylaminophenyl) ethylene.

4. The composition of claim 1 wherein the constituents are Mg.l,1-bis-p-dimethylaminophenyl ethylene 1-100 4-picoline-N-oxide O.110Triphenylstibine 0.1-20 2,6-di-t-butyl-p-cresol 0.1- Iodoform -1000 5.The composition of claim 1 wherein the constituents are 1,1-bis-(p-dimethylaminophenyl) ethylene-50 mg. Iodoform200 mg.

4-Picoline-1-oxide-5 mg. 2,6-d-t-butyl-p-cresol25 mg.

Triphenylstibine1 0 mg.

Polystyrene 10% in benzene3 cc.

Acetone-1 cc.

Benzene-4 cc.

6. A dry working photographic process which comprises preparingcomposition of claim 1 in a thin film; exposing said composition to apattern of radiant energy, whereby a neutral or nearly black imageprints out directly as a result of said exposure; and fixing said .imagein said composition by heating the same.

7. The photographic process of claim 6 wherein the thin film is given ablanket exposure to suitable radiation in the visible prior to exposingit to a pattern of radiant energy and the radiant energy to which it isthen exposed has a wavelength greater than 6500 angstrom units.

References Cited UNITED STATES PATENTS 3,436,353 4/1961 Dreyer et al.96-90 NORMAN G. TORCHIN, Primary Examiner JUDSON R. HIGHTOWER, AssistantExaminer

